Semiconductor Light Emitting Device Scattering Particles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor light emitting devices using phosphors for white light production face challenges in uniform color mixing and light efficiency due to uneven excitation and reabsorption of phosphor emissions, leading to reduced light output and color breakup issues when viewed from different angles.
Innovation Solution
A semiconductor light emitting device configuration that includes a light emitting element, a phosphor layer with scattering particles dispersed in a transparent medium, and a fluorescent reflection film, where the scattering particles selectively scatter excitation light to enhance uniform phosphor excitation and reduce reabsorption, while the fluorescent reflection film optimizes the reflectance for phosphor output wavelengths, improving light efficiency and color rendering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If phosphor is used to convert light wavelength, then white light can be produced, but uneven excitation and reabsorption of phosphor emissions occur leading to reduced light efficiency and color breakup
Solution Approach 1:
A transparent resin layer is introduced as an intermediary medium between the blue light emitting element and the yellow phosphor. This resin layer has a refractive index that is optimized to reduce reabsorption of phosphor emissions while maintaining uniform excitation. The resin acts as a mediator that improves light extraction efficiency and reduces color breakup by controlling the optical path and minimizing unwanted interactions between the emitting element and phosphor particles.
2Device complexity
If phosphor layer is placed directly on light emitting element, then compact structure is achieved, but uneven excitation and reabsorption reduce light output
Solution Approach 1:
The refractive index of the transparent resin layer is specifically optimized to resolve the contradiction between compact structure and high light output. By selecting a resin with appropriate refractive index parameters, the design achieves both compact integration and improved light extraction efficiency. The refractive index matching reduces reabsorption losses and enhances uniform excitation of the phosphor layer, thereby increasing overall light output while maintaining a compact form factor.
3Stability of the object's composition
If scattering particles are added to phosphor layer, then uniform excitation is improved, but device complexity increases
Solution Approach 1:
Scattering particles are selectively incorporated into the transparent resin layer at specific locations and concentrations to achieve uniform excitation of the phosphor. The scattering particles are not uniformly distributed throughout the entire device but are strategically placed in the resin layer where they can effectively diffuse excitation light without adding unnecessary complexity to other parts of the device. This localized approach improves chromaticity uniformity while minimizing overall device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The configuration achieves a high-quality white light with improved light emitting efficiency and reduced color breakup, providing a uniform chromaticity distribution and enhanced light output by minimizing unnecessary scattering and reabsorption, thus improving the overall performance of the semiconductor light emitting device.
Implementation Method 1
the scattering particles selectively scatter excitation light to enhance uniform phosphor excitation and reduce reabsorption
Implementation Method 2
The phosphor is excited by the excitation light so as to emit a fluorescence
Implementation Method 3
the fluorescent reflection film optimizes the reflectance for phosphor output wavelengths
Data Source
AI summary
According to one embodiment, a semiconductor light emitting device includes a light emitting element, a phosphor layer, and a fluorescent reflection film. The phosphor layer has a transparent medium, a phosphor dispersed in the transparent medium, and a particle dispersed in the transparent medium. The phosphor is excited by the excitation light so as to emit a fluorescence. The particle is a magnitude of not more than 1/10 a wavelength of the excitation light. The particle has a different refractive index from a refractive index of the transparent medium. The fluorescent reflection film is provided between the light emitting element and the phosphor layer. The fluorescent reflection film has a higher reflectance with respect to a fluorescent wavelength of the phosphor, than a reflectance with respect to the wavelength of the excitation lights.